国家冰川冻土沙漠科学数据中心

元数据

名称	Overpressure Generation Mechanisms and Its Distribution in the Paleocene Shahejie Formation in the Linnan Sag,Huimin Depression
科技资源标识	CSTR:11738.14.NCDC.XDA14.PP5788.2024
DOI	10.3390/en12163183
数据共享方式	开放下载
摘要	The Linnan Sag is one of the main oil-producing units in the Huimin Depression, Eastern China, and the pore pressure gradients obtained from drill stem tests (DSTs) range from 9.0 to 16.0 MPa/km. Uncertainty about the origin and distribution of abnormally high pressures in the Linnan Sag has led to different interpretations of hydrocarbon accumulation and resource assessments, and it interferes with safe drilling. In the Linnan Sag, mudstone compaction curves are substantially affected by several non-compaction factors, and the normal trend of the compaction curve is difficult to determine. The determination of the origin and distribution of overpressure in the Linnan Sag is a challenge. In this study, the factors that may affect mudstone compaction—such as the shale volume, higher calcareous, and organic matter content—were carefully examined and processed. The pressures in the mudstones were estimated by the corrected mudstone compaction curves, which were compiled from acoustic, density, and neutron logs, and calibrated using DST and mud weight data. The log response–vertical effective stress and acoustic velocity-density crossplots were used to identify the mechanisms that generate overpressure. The comprehensive compaction curve shows that the mudstones in the overpressured layer exhibit clear disequilibrium compaction characteristics. The logging response crossplots demonstrate that those overpressured points were consistent with the loading curve. The findings suggest that, the fundamental mechanism resulting in overpressures is the disequilibrium compaction of thick Paleocene mudstones. Hydrocarbon generation and vertical transfer of overpressure may be the main unloading mechanisms, which corresponds to the overpressure points that deviate from the loading curves. Since organic matter cracking may occur in formations at depths greater than 4000 m (Ro > 1.0%), the contribution of hydrocarbon generation to overpressuring is expected to be limited. The transfer of overpressure through opening faults is therefore considered to be the main cause of higher overpressure in local sandstones. The overpressures in the mudstones are characterized by a gradual decrease from the center to the margin in the Linnan Sag. The pressure in the isolated sand bodies are generally similar to that in the surrounding mudstones, whereas it can be lower or higher when the overpressure in the sand bodies are vertically transferred by faults to other pressure systems. The results of this analysis provide an indication of the magnitude, mechanism, and distribution of overpressure in the Linnan Sag. This insight can be used to guide further exploration of the Linnan Sag and similar geological basins.
学科分类	170.50
关键词	overpressure mechanism disequilibrium compaction fluid expansion vertical transfer Shahejie formation Linnan Sag
作者	Chao Li,Xiaorong Luo,Likuan Zhang,Bing Wang,Xiaoyan Guan,Hongmei Luo,Yuhong Lei
数据量	5.7 MiB
论文类型：	journal
论文网址：	https://www.mdpi.com/1996-1073/12/16/3183
期刊名称：	Energies
出版时间：	2019-09-01

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数据引用

Chao Li,Xiaorong Luo,Likuan Zhang,Bing Wang,Xiaoyan Guan,Hongmei Luo,Yuhong Lei. Overpressure Generation Mechanisms and Its Distribution in the Paleocene Shahejie Formation in the Linnan Sag,Huimin Depression. 国家冰川冻土沙漠科学数据中心(http://www.ncdc.ac.cn), 2024. https://cstr.cn/CSTR:11738.14.NCDC.XDA14.PP5788.2024.

许可协议

本作品采用知识共享署名 4.0 国际许可协议进行许可。

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项目信息详情

项目名称：深层油气形成与分布预测
项目编号：XDA14010000
项目类别：中国科学院战略性先导科技专项（A类）